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1004 The Dynamic Cell > musclees! > Flashcards

musclees! Flashcards

1
Q 
which neurotransmitter is typical at a neuromuscular junction?
A acetylcholine
B dopmine
C acetylcholine esterase
D glutamate
E serotonin
A

OPTION A
an oldy but a goofy!
> option C is an enzyme (-ase)

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2
Q 
which protein does calcium bind to on the thin filament to allow exctiation contraction coupling?
A tropomyosin
B troponin
C actin
D myosin
E ATP
A

OPTION B

which relases tropomyosin alowing mysin head to bind

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3
Q 
which receptors dihydropyridine receptor (DHPR) conformationally couple with to release calcium from SR?
A voltage gated calcium channels
B tropomyosin 
C ryanodine receptors
D acetylcholine receptors
E sarcolemma
A

OPTION C YEAH
> key word SR so this is just skeletal muscle
> key word also receptors

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4
Q 
which length of striation spacing do skeltal muscle ususally function at
A 200 micro m
B 2cm
C 2micro m
D 3.5 cm
E 1.5 micrro mete
A

2mircrometers

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5
Q

WHAT is the purpose of gap jucntion in cardiac muscle?
allow electrical activity between adjacent muscle fibres
allow physical spaces between adjacent muscle fibres
allow mechanical activity between adjacent muscle fibres

A

OPTION A
electricity yeaha
mechsnci al activty are more like physical barriers

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6
Q

does the SAN allow a slow or a fast response?

A

slow response!

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7
Q 
which ion(s) influx during phase 0 of slow response cardic cells to cause depolarisation?
calcium
potassium
sodum
chloride
A

calcium and sodium!

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8
Q

'’the resting membrane potential of pacemaker cells in cardic muscle is unstabe’’
true of false?

A

turee

not flat

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9
Q

in cardicac muscle are the DHPR and ryanodine receptors conformationally coupled?

A

NO THY ARE NTOT
> come together to function but main source of calcium is extracellular instead of from ER
> Key word cardicac muscle (they ARE in skeletal muscle)
> calcium induced calcium signalling instead on ryanodine receptor

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10
Q

which of these is a function of smooth muscle
allow us run
pump blood around the body
move a bolus of food down oesphogus by peristalsis
ride a bike

A

OPTION C

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11
Q 
name the presynaptic terminals that release neurotransmitter onto smooth muscle
autonomic reflex
varocisties
presynaptic bulb
acetylcholine
A

varicosities which are presynaptic terminals close to the effector cells
> presynaptic bulb forms part of the varicosity

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12
Q 
where is calcium transpoted from to allow the contraction of smooth muscle?
SR
Extracellualr Fluid
Intracellular Fluid
ER
A

SR and ECF!
yaay
> SR as its just the muscle

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13
Q

which is true?
A skeletal muscle bigger than smooth muscle fibres
B smooth muscle cells are mutlinucleate
C skeletal muscle dont contrin sarcomeres
D cardiac muscle under autonomic control
E main calcium store for skeletal muscle is extracellualr

A

OPTION C

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14
Q

WHICH is false - relasted to cardiac muslce and fast repsonse cells
A reploarisation due to potassium eflux (phase 1)
B in fast reponse cells , phase 4 has a more negative resting membrane potential than baseline
C fast repsonse cells have stable resting membrane potential
D phase 0 due to sodium entry
E sinoatrial node is a type of fast reponse cells

A

OPTION E

- SAN is a Slow reposnse cell

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15
Q

which muscle(s) is striated?

A

sketletal and cardiac!

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16
Q

Which of the following is not a step in excitation contraction coupling in skeletal muscle?
Propagation of action potential into T-tubule
Activation of ryanodine receptor triggering conformational change in T-tubules and coupling with dihydropyridine
Release of Ca+ from sarcoplasmic reticulum
Binding of Ca+ to troponin causing conformational change in tropomyosin
Cross bridge formation and power stroke

A

OPTION B
DHP receptors on the T-tubule are activated
Ryanodine receptors on SR

17
Q

what are T-tubules?

A

where the sarcolemma folds into the sarcoplasm! (like a crypt of lieberkuhns)

18
Q

A cardiac cell that has a stable resting membrane potential and a phase 4 resting membrane potential that is more negative that it’s phase 0 resting potential is likely a..?
slow response cell
fast resposne cell

A

FAST REPONSE CELL
e.g. purkinjie fibre or Atria+Ventricles myocytes
> slow response cells have unstable resting membrane

19
Q

which is the thick filament

actin or myosin?

A

myosin is thickk

20
Q

in cardiac muscle what do the desomosomes and gap jucntion allow

A

> mechnincal jnctiion between adjacent fibres

> electrical connectivitity between adjacent fibres

21
Q 
where in cardiac cells is the action potential initiated
A SAN
B AVN
C bundle of His
D purkinjie fibres
A

SAN (the pacemaker cells) which have a slower resposne than cardiac cells

22
Q

what causes the unstable resting memebrane potential in pacemaker cells?

A

funny channels which can open up below thereshold (hyperpolaried state) and Na+ can creep in

23
Q

ture of false?

all muscles have both the absolute and relatvie refractory periods

A

FALSE
cardiac muscle only has the absolute = full hearbeats
> if not then there would be unsteady heartbeat/firbrilations
How is this done? sodium channels remain INACTIVE

24
Q

what is tetanus?

A

the prolonged contraction of a muscle due to rapidly repated stimuli

25
Q

in cardiac muscles there are scaffolding proteins (e.g. titin) what do?

A

prevents the overstretching of the heart

26
Q

what is postive chronotropy
what is postive ionotropy
what is postive lusitropy

A

increases rate of contraction
increases force of contraction
increases rate of heart/myocardial relaxation

27
Q

give an example of a single unit smooth muscle

visceral smooth muscle/myogenic

A 
GI tract
uterus
bladder
> has gap junctions allowing propogation of AP so it works as a unit
>> fucntional synchtium
28
Q

give an example of a multiunit smooth muscle/ neurogenic

A

iris
airways
>each unit contracts indiviually
> NO gap junction so can function independently

29
Q

one z-disc to anither Z-zone is called?

A

sarcomere! the contractile unit of skeleltal muscle!

30
Q

what is the latch state?

A

allows sustained smooth muscle contraction as cross bridge cycling can occur with LESS ATP USAGE
> some cross bridges are dephosphorylated but some remain locked together

31
Q

does a sphinchter has tonic or phasic contraction/

A

tonic! - for ususally contracted muscles

phasic for relaxed muscle or phases between contract and relax - oesphagus or ntesintes

32
Q

In smooth muscle functioning, what happens between calcium binding to calmodulin and the binding of myosin to an actin molecule?

A Myosin Phosphatase dephosphorylates myosin.
B Propagation of calmodulin is stimulated.
C Calmodulin activates Myosin Light Chain Kinase.
D Phospholipase C activates calmodulin.
E Neruotransmitters are released but no action potenital is fired.

A

OPTION C

C: occurs after cross bridge binding causing relaxation

1004 The Dynamic Cell (10 decks)

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